Lifting jack



June 30. 1931. H, ALBER'HNE 1,812,577

LIFTING JACK Filed April 27. 1928 y Vy INVENToR Herman, Alberh'ne 'ATTORNEY Patented June 30, 1931 UNITED STATES PAiTENT OFFICE HERMAN ALBERTINE, OF E'AST RUTHERI0RD,. NEW -`I'E.`.R-SEYL ASSIGNOR T0 ROGERS l.PB'OD'UL'LS COMPANY, INC., A. C0RIPORfAlIOIN' OF NEW JERSEY :summe .Tacx

Appliation med April 27,

My present invention relates more particus larly to so-called hydraulic jacks, which comprise piston and cylinder elements operated by hydraulic pressure'I of a liquid, usually oil,- which is-pumped into the cylinder space to force the operative expansion or lifting movement of the relatively f novable parts and in the present disclosure of the device, the cylinder is fixed and the pisto'n element is the one forced upwardly by the liguid to produce the desired lifting effect. t will be evident that the main features of my invention are highly desirable and that man of its novel features are very useful throug a wide range as to power of jacks of this general type.v

The hydraulic method of operation makes it easy to apply relatively great lifting effects by relatively small manual effort and such great-and easily applied lifting effects arelikely to make trouble especially at the end .of the lift of the plunger, where further movement must be stopped. For this purpose, mechanical stops have been, employedA 25. on the cylinder and on the plunger respectively which engage at the upper end of the lifting stroke of the plunger. p But in such' case continued operation `of the Ipump produces undesirable strains, high pressures and V3:) stresses that sometimes wreck the pump.

Means for cutting olf the ower, as byclosing .the intake to the pump, ave also been emv My present invention includes means for by-passing the fluid liquid from the output to the intake of the pump when the pressure exceeds a predetermined maximum. This p feature serves not only to limit the upward movement ofthe plunger but also to prevent excessivefpressures regardless of the height ofthe movable element. This' willprevent damage to the pump, certain cases', as where attempt is made to lift a load far in excess of the designed power of the jack.

A further feature of the invention is means for adjustin the reure' at which the lay-pass relief vice gins to operate.v v Other features lof the. invention 'relate t arragin'glthe' relief devieein the-end ofthe plunger; tothe assemblypf the relief and 192s. serial ramasse.'

fadjustin devices in a single element which -the lplunger and the inner surface of the cylinder, the-latter bein in communicatin with a surrounding res rvoir that supplies the pump.-

Other features and advantages will appear upon consideration of the following description and the accompanying drawings, where- 1n Fig.i l is a view in lon 'tudinal section;

n Fig. 2 is a view on a rger scale of a detail of Fig. 1; and

Fig. 3 is a view. in cross section on the line 3 3 of Fig. 2.

The 'ack includes. a substantial base 10, prefera ly of cast iron, having a threaded socket 11 which receives the lower end of an upstandin cylindrical member or cylinder 12, prefera ly a heavy drawn steel tube, forming the outer wall of the annular reservoir 13. Countersunkv in the bottom, of socket 11 is a second 'socket'` 14a1so threalled land receiving the threaded lower end of a similar cylinder or v cylindrical member 15 constituting a guide member in which a plunger 16 is telescopically mounted. The cylinder 12 is closed at the top by a head in the form of a screw plug 17 havin .a flange which engagesV the top of the cylin er .when these parts are assembled. The head orplug- 17 closes the reservoir space at the top and is provided with a central dpening 18 'to accommodate the plunger or piston 16. The inner wallof this ,opemng is cut away to provide a beveled shoulder 19, .cooperating with a scr-ew' bus'hing 20' to :retain ,and compress placlng 21. The packing is wedged betweerrt e shoulder and the bushing and insures irm noir-leak,

sliding contact with the plunger.' "The annular head or cap. 17,- bushing 20 and acking- 21' have'fa'guidmg and oilwiping ctin im rtant than their function of preventing leagesince imnormal operathe reservoir.

tionthere islv'ery little .internal The guide cylinder. 15 is open at the top and the stem of the plunger 16 has a relatively loose fit therein affording an annular space 27 so that the oil can flow in either direction, between said space and the pump reservoir. At its. lower end, the plunger 16 has an internally threaded bore 22 and `is in engagement with an annular collar or piston head 23, having a close fit in the cylinder 15 and provided with a central bore 24 normally maintained in alignment with the bore 22 in the piston by means to be described more fully hereinafter. This piston head 23, which is preferably of metal, is formed with an annular chamber 25 communicating interiorly with the bore 24 and a restricted passage 26 extends along its upper surface affording an outlet to the annular space 27 between the plunger 16 and the cylinder 15.

Upon the lower face of the annular head 23 is an annular washer 28, preferably of leather, which is in turn engaged by a downwardly turned annular cup washer 29, also preferably -of leather. The head 23, washerV 28 and cup leather 29 are all clamped in position with reference to the plunger stem 16 by means of a bolt element 30 formed with a hollow tubular shank 31 which serves as a valve casing. The shank is exteriorly threaded to ,fit the bore 22 of thef plunger 16 and is provided with a head 32 of greater cross section providing a clamping shoulder 33 which engages a clampingwashei` 34 the upper surface of which clamps the central'portion of the cup washer 29. By screwing the valve casing 30 into the bore 22 of the plunger 16, the piston head and washers are clamped against the lower end of the plunger with the proper degree of pressure. The

vupper surface of the washer 34 has annular ribs 35 which may be forced into cup leather 29, to hold it securely and t-o prevent leakage of the liquid interiorly through the .central perforation of the cup. l l

The hollow stem 30 is utilized as the casing of a pressure relief or safety valve. It is provided at its lower end with an axial passage 36 communicatin at its upper end with a. larger central bore -3 extending downward from the upper end of the stem. At the lower end of the bore 37 and surrounding the upper end of the passage 36 is a. conical valve seat 38 provided for co-operatioi-with a valve member or ball 39 fto close the passage 36. This b'all 39V is held in the tip of the tapered lower end of a member 40 ina socket which contains slightly more than the upper half of the ball and therefore prevents separation.

Preferably, the ball is secured either by braz-4 ing or by spinning in the tapered edges of the adjacent cone surface. The upper end of the member '40 is formed with a reduced shank 41 extending upwardl from an annular shoulder 42 and is urge in a direction to` close the passage 36 by a helical spring 43 of which the lower end surrounds the shank 41 and engages the shoulder 42 and the upper end engages a screw plug 44 threaded into the enlarged upper end of the bore 37 in the valve casing. Screwing the plug 44 in orvvout, as by a screwdriver engaging the slot in the upper end of the plug varies the compression of the spring, to set it for any desired tension within the limits of the apparatus. An important point is that the adj ustment for a desired relief pressu-re may be made before the apparatus is assembled and this makes it easy to standardize the operation of all jacks of the same size and lifting power. When the pressure in the cylinder 14 beneath the plunger 16 becomes excessive, the ball valve 39 is forced back against the resistance of the spring 43 thus permitting the liquid to pass upwardly through ,the passage 36 into the bore 37 and out therefrom through a passage 45 provided for the purpose into the annular chamber 35 and outwardly therefrom through the restricted passage 36 to the annular space 27 from whlch it can flow back to the reservoir 13. It will be seen that the passage 45 is made of sufficient size to assure communication with the annular chamber 25 regardless of different longitudinal adjustments of the valve casing 30, and

that ther annular chamber assures communi- 9 cation regardless of angular adjustment of the valve casing. As before explained, complete assembly of the relief valve element and adjustment of the tension of the spring 43 may be effected before screwing the tubular shank 31 into the lower end of the plunger. The pumping means for forcing fluid from the reservoir 13 to the interior of the cylinder 15 below the plunger, includesfa plunger 46 vertically movable 1n a cylinder 47 formed in a lateral extension 48 of the base 10. At the lower end of the cylinder 47 is a conical valve seat 49 adapted to cooperate with a valve member or ball 50 to form a. check valve-l and prevent'liquid drawn into the cylinder 47 through a passage 51 extending from a reservoir 13 to the valve seat 49, from returning to the reservoir when the pump plunger 46 is depressed. At its lower end,A the pump plunger 46 is, provided with a cupped `flexible washer 52 held thereagainst by a screw 53 so as to avoid leakage past the head of the piston orI plunger when it is depressed during a pumping action. `During such downward movement of the plunger 47, liquid drawn into the cylinder 47/ from the reservoir 13 will be forced from the cylinder, through a passage 54 and past a check valve 55 into the cylinder 15.

As here shown, the check valve 55 is a ball valve and the ball thereof may be kept from movement too far from its seat by a plate 456 having a central opening of less diameter than the diameter of the ball and clamped in position between the baseand the lower end of the cylinder 15.

plunger 56, liquid will be drawn from the' reservoir 14 and forced into the lower end of /the cylinderv 15 and the plunger 16 may be raised to the desired position. If the operation of the pump is continued and the load on the piston 16 does not require an increaseof pressure above that for which the relief valve device is set, the plunger` will rise until the upper side of the piston head 23 engages the lower face of the head 17. Then continued movement of the pump plunger would effect increase of pressure in the cylinder 15 thus tending to subject parts of the jack to undue stresses. When,'however, the pressure for which the relief device is adjusted is reached,

the ball 39 will be forced upwardly` in the.

valve casing and the-pressure in the cylinder 15 below theplunger will be relieved by passage of liquid therefrom through the passage 36 to the interior of the valve casing 30 and outwardly therefrom through .the passage45, the annular chamber 25 and the restricted passage 26 and over the top of the i cylinder 15 to return to the liquidremaining in the reservoir. The plunger is lowered by releasing the oil from beneath the piston through relief outlet 60. This outlet commuy piston to permit escape of oil when the presnicates with a valve controlled passage leading back to the reservoir 14. This release passage and its valve are not shown because they,"

are preferably the same as shown in patent to Zabriskie No. 1,611,703. Y

It should be understood that various changesv may be madelin the construction and arrangement of the parts without departing from the true scope and spirit of the invention.

I claim:

1. A jack, including an oil reservoir, a cylindrical ,member constitutlng'theinner wall v l, tenorly threaded bolt.

of said reservoir, a piston in said cylindrical member having a stem guided in said reservoir, a pump for delivering oil from the reservoir to the interior of'said'cylindrical member, a safety valve in the lowerend of said sure exceeds a predetermined limit, and means fori regulating said safety valveto determine the pressure at which it isto be operated, said i safety valve and regulating means beinga removableunit 'structure so that it can be.'

separately adjusted for the desired pressure limit while removed from the ]ack.

' Y, l2. A jack, including a@ guide cylinder, a

reservoir around-said cylinder and communicating therewith at the top, means for pumpi g liquid from said reservoir into. the lower end of saidcylinder, a plunger having a loose it in said cylinder and providedat its lower end with a threaded axial bore, means at the bottom of the plunger. for effecting a liquid tight seal in said cylinder and including an annular head fitting the interior of said cylinder and having a central passage of substantlally the same cross section as said bore communicatingwith an annular passage at the upper surface of said annular head where it engagesthe lower end of the lunger and a restricted Vpassage extending rom said annular passage to the outer surface of said plunger, and a safety valve device having an externally threadedportion passing through said annular head and screwed into said bore in the plunger and having a head by means of which said annular member is clamped against the lower end of said plunger.

3. A jack, including a guide cylinder, ay

land provided a its lower end with a. device fitting said cylinder closely and having a passage therethroughlfrom the bottom side thereof upwardly to the lower end of said plunger and outwardly through a restricted section' to the outer surface of the plunger o form a4 by-pass and a safety valve assembly extending through said by-pass device into the lower endof-the plunger and adapted to prevent the passa e ofviuid from said cyl.- inder through sai by-pass until a predetermined pressure is exceeded.4

4. A jack, including a guide cylinder, a',v plunger having a loose fit in said cylinder and provided at its lower end with a device fitting said cylinder closely and having av passage therethrough from the bottom side.

thereof upwardly to the lower end of said plunger and outwardly through a restricted section to the outer surface of the plunger to form a by-pass vand safety valve assembly extending through saidf by-pass device into thelower end of the plunger and adapted to prevent the passage -of fluid fromvsaid cylinder through said by-pass until a predetermined pressure is exceeded, said safety' valve assembly being in the form of a hollow, ex-

5. A jack, including a cylinder and a plunger, the plunger including a stem of smaller diameter than the cylinder and a pisizo cylin er and in combination with said parts v a bolt threaded in said axial passage to clamp said cup leather in operative relation to the piston head, said .holt having longitudinal hollow portion formed with a valve satand housingan; overloadvalve and having a rei lief passage from the compression cylinder to the valve and an outlthrough said lateral passage into said space between vthe stem and cylinder. i

L 6. A jack, including a. guide cylinder, a plunger having a loose lit in said cylinder and provided at its lower end with a device fittingl said cylinder closely and having a passage therethrough from the bottom side thereof upwardly to the lower end of said plunger v and outwardly through a restricted section thereof to the outer surface of the plunger to form a b pass and a. safety valve device extending t rough said by-pass device into.

the lower end of the plunger and adapted to prevent the passage of fluid from said cylinder through said by-pass until a predetermined pressure is exceeded, said safety valve device including means for adjusting the pressure at which relief will be effected.

7 A jack, including a guide cylinder, a plunger having a relatively loose t in said cylinder and having an-internally threaded axial Ibore at the lower end thereof, an annular head at the lower end of said plunger itting` said cylinder and having at its upper face an annular chamber communicating with its central opening and a restricted passage from said annular chamber to the outer suri face of theoplunger, and means for preventing passage of fluid through said washer including a relief valve device having a tubular shank passing through the central opening of said head and threaded into said bore in the plunger, said tubular shank having an openingto communicate with the lannular chamber in said washer and said relief valve device having at the lower end of said shank a spring controlled reliefvalve.

8. A jack, including a guide cylinder, a plunger with packing to form a piston, having an internally threaded axial bore at the lower end thereof, and a restricted passage from said bore chamber to the outer surface of the plunger above the acking and means for preventing passage o Huid throu h said bore and passage, including' a relie valve device having a tubular shank threaded into said bore in said plunger, a valve seat and valve in said valve device at the upper end of a passage communicatin with the interior of the cylinder, and means or yieldably holding said valve member against said seat, in-

cluding` a helical spring in said shank and screw plug adjustably threaded into the upper end of said tubular shank andengaging the upper end of said spring.

Signed at New York, in the county of New York and-'State of New York, this 26th day 0f April, A. D. 1928.

ALBERTINE. 

